Power operated apron for tractor scrapers



Filed June 10, 1965 1967 A. R. SWANSON. 3,352,037

POWER OPERATED APRON FOR TRACTOR SCRAPERS 2 SheetsSheet 1 ,70 Inn v Q 00m m m m m FIG. 6

FIG. I

INVENTOR ALLAN R. SWANSON ATTORNEYS MIG INVENTOR ATTOR NEYS Nov. 14,1967 A. R. SWANSON 7 POWER OPERATED APRON FOR TRACTOR SCRAPERS FiledJune 10, 1965 2 Sheets-Sheet 2 5.2% 4 5 w v i? B 1 a A: J Mk F e f FIG.4

ALLAN R. SWANSON United States Patent 3,352,037 POWER OPERATED APRON FORTRACTOR SCRAPERS Allan R. Swanson, St. Joseph, Mich., assignor to ClarkEquipment Company, a corporation of Michigan Filed June 10, 1965, Ser.No. 462,820 6 Claims. (Cl. 37-129) ABSTRACT OF THE DISCLOSURE Poweroperated apron for opening and closing a bowl of an earth moving scraperin which cam means and cam follower means between the apron and the bowlare associated with power actuating means for effecting application oftorque of the power actuating means to and for moving the apron.

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The present invention relates to power operated aprons for tractorpropelled earth moving scrapers.

In the known apparatus, to which the present invention relates scrapersare provided which comprise an earth carrying bowl open at its forwardor leading end, and at the lower edge of which a cutting edge isprovided for engaging ground or other material to be displaced into thebowl. An apron pivotally mounted on the bowl is conventionally providedand which apron is movable between open and closed positions for openingand closing the open end of the bowl. Thus, when a bowl of such ascraper is charged with dirt or other material collected in it, theapron is disposed to closed position for transport of the collectedmaterial to a place of deposit. The bowls of such scrapers are generallyof large capacity, many of which are designed to accommodate loads ofthe order of 25 or more cubic yards of dirt. In order to open the apronof a scraper carrying a load of the order indicated, a high torque isrequired in that part of the load in the bowl is resting on the apronand tends to hold the apron in closed position. Also, in the closedposition of the apron, the center of the mass of the apron is at asubstantial distance from the pivot axis of the apron on the bowl. Afterpredetermined initial opening movement of an apron with respect to thebowl and as the dirt falls from the apron, the weight of such dirt nolonger has to be overcome in the further opening movement of the apron,and the center of mass of the apron moves progressively closer to thepivot axis of the apron on the bowl. Thus, in the arrangements referredto, maximum torque is required to move an apron from its closed positiontoward its open position during an initial predetermined range ofinitial opening movement of the apron with the amount of torque tocontinue to raise the apron decreasing after such predetermined range ofinitial opening movement of the apron.

It is an object of the present invention to provide a simple arrangementof components between an apron pivotally mounted on the bowl of ascraper embodying cam means and cam follower means associated with theapron and the bowl together with power actuating means for effectingrelative movement of the cam means and cam follower means, and in whicharrangement the cam means affords desired application of torque of thepower actuating means to the apron in movement of it relative to thebowl.

It is a further object of the present invention to provide cam means andcam follower means for association with the bowl and apron elements of ascraper together with power actuating means for effecting relativemovement of the cam means and cam follower means and in which such cammeans provides for substantially ice constant application of the torqueof power actuating means to the apron over a predetermined initial rangeof opening movement of the apron, and for the lessening of theapplication of torque of the power actuating means in the continuedopening movement of the apron beyond the predetermined range of initialopening movement of the apron.

In accordance with the foregoing objects the present invention providesan arrangement in which maximum torque of the power actuating means maybe utilized in the initial opening movement of the apron, and afterwhich the torque decreases as the load of the apron decreases upon itsfurther opening and to increase the speed of angular velocity of theapron to fully open position, which is highly desirable for the rapidand efiicient discharge of a load from the bowl of the scraper.

A further object of the invention resides in the provision of doubleacting power actuating means operable in one direction of actuationthereof to provide the aforenoted advantages and which when operated inthe other direction of actuation thereof effects power closing of theapron at maximum torque of the power actuating means to close theopening of the bowl.

In an apparatus in accordance with the last noted object, in the eventdirt in the bowl or foreign material is disposed at the cutting edge ofthe bowl, the lip of the apron is positively forced against suchmaterial to enable full closing of the apron with respect to the bowl.

The above and other objects and advantages of the invention will appearfrom the following detailed description of a preferred embodiment of theinvention.

Now in order to acquaint those skilled in the art with the manner ofconstructing scrapers in accordance with the principles of the presentinvention, there is described below in connection with the accompanyingdrawings a preferred embodiment of the invention.

In the drawings:

FIGURE 1 is a side elevational view of a scraper embodying the presentinvention;

FIGURE 2 is a detail vertical sectional view taken substantially alongthe line 22 of FIGURE 1 looking in the direction indicated by thearrows;

FIGURE 3 is a detail vertical sectional view taken substantially alongthe lines 3-3 of FIGURE 1 looking in the direction indicated by thearrows;

FIGURE 4 is a detail vertical sectional view taken substantially alongthe line 44 of FIGURE 1 looking in the direction indicated by thearrows;

FIGURE 5 is a detail vertical sectional view taken substantially alongthe line 55 of FIGURE 1 looking in the direction indicated by thearrows; and

FIGURE 6 is a plan view showing the relationship of certain portions ofthe bowl, apron and associated parts illustrated in FIGURE 1.

Referring now to FIGURE 1, there is shown a scraper 10 comprising a bowl11 and an apron 12 for the closing of the forward or open end of thebowl 11. The apron 12 is shown in full lines in its closed position forclosing the open end of the bowl 11 and in dotted line in its fully openposition with respect to the bowl.

The scraper 10 may be drawn to the left as viewed in FIGURE 1 in aconventional mannerby a tractor, a portion of which is shown at 14. Therear end of the scraper 10 may also be supported in a conventionalmanner by wheel means indicated at 15.

The bowl 11 per se is of conventional known construction and comprises apair of vertically spaced apart side walls 16, truly one being shown inFIGURE 1, a bottom wall 17 extending between the side walls 16 and anend wall 18 for closing the rearward end of the bowl. The forward end ofthe bowl is open andat'the lower edge of which a cutting edge member 19extends transversely of the scraper to engage the ground with the apron12 in a partially open positoin and in movement of the scraper to theleft, as viewed in the drawing, for loading the bowl with dirt to becollected at a first position for deposit elsewhere. It will beunderstood that the apparatus also includes conventional and knowncontrol means (not shown) for raising and lowering the scraper in earthcollecting and depositing operations. Suitable channel reinforcingmembers are provided at opposite side walls of the bowl, such as channelmembers 22, extending lengthwise of the bowl adjacent the upper edges ofthe rearward portions of side walls, and rear channel reinforcingmembers 23 at the rear of the bowl between which a transverselyextending tube 24 extends for reinforcing the rearward end of the bowl.Upwardly and forward-1y inclined channel members 25 extend from thelower rearward end of the bowl to the hitch assembly as shown at 26 formounting the scraper to the tractor. Additional reinforcing channelmembers such as shown at 27, 28 and 29 are provided to provide strongcross reinforcement of the scraper bowl to enable the handling of largeloads as, for example, the order previously noted of 25 cubic yards andmore. The apron 12 as best seen in FIGURES l and 6 comprises a pair ofpivot arms 30 lying outwardly of the side walls 16 of the bowl 11, andinner side walls 32 of the apron with the outwardly extending ends ofthe pivot arms 30 being welded to side wall plates 32 as indicated at33. The arms 30 and side wall plates 32 of the apron may be reinforcedby a gusset 34 as shown in FIGURE 6. The opposite or inner ends of theapron arms 30 as best seen in FIGURE 1 are pivotally mounted about afixed axis of rotation at and laterally of the side Walls 16 of the bowlas indicated generally at 31. As best seen in FIGURE 5, the ends of eachof the arms 30 has a bearing hub 39 secured thereto provided with abearing sleeve 35 journalled on a pivot pin 36 mounted between lugs 37and 38 with the lug 37 being secured as by welding to the upper end ofchannel strut 28, and the lug 38 being secured to the adjacent side wall16 of the bowl 11.

Each pivot arm 30 is formed with cam means 40 comprising a cam slotreceiving, as best seen in FIGURE 2, a roller 42 of cam follower means43. The cam follower means 43 further comprises a stub shaft member 44for supporting the roller 42 for rotation at one end thereof with therebeing a bearing assembly 45 arranged between the roller 42 and the shaft44, Shaft 44 at its end opposite roller 42 is rigidly fixed in a slidemember 46 which is mounted for reciprocatory horizontal sliding movementin track means 47 defined by opposed upper and lower flange framemembers 48 and 49 formed to provide channels in which the upper andlower edge portions of the slide member are disposed. The flanged framemembers 48 and 49 are rigidly secured as by welding to the adjacent sidewall 16 of the bowl 11 and the lower flange frame member 49 adjacent theportion thereof extending rearwardly of' the bowl is further secured, asby welding, to the upper wall of channel member 22. 1

Poweractuating means, indicated generally at 50, may by way of example,comprise a hydraulic piston and cylinder assembly 52' having a cylinderassembly 53 and piston rod means54. As best seen in FIGURE 3, the reartransversely extending tube 24 supports a pair of spaced apart upwardlyextending lugs 56 for supporting a pivot pin 56 providing an anchormounting for the mounting flange 59 extending rearwardly of the closedend of cylinder assembly 53. The outwardly projecting end of piston rodmeans 54 is connected by pin 60 mounted between spaced apart lugs 61extending laterally away from the end of slide member 46 opposite roller42. The hydraulic cylinder assembly 53 as shown may be of the doubleacting type and for this purpose is provided with fluid connecting ports57 and 58 through which fluid under pressure may be selectivelyadmitted'to one side or the other of the piston 62 of the piston means54. The double acting hydraulic piston and cylinder assembly is of knownconstruction and is operative in opposite directions by the selectiveadmission of fluid under pressure through port 57 or port 58 so that thepiston means 54 is power driven in either direction by relative movementwith respect to the cylinder 53.

The aforementioned cam means 40 may, as is well known in the cam art, bedevised to provide selected torque transmitting characteristics of thepower actuating means to the apron 12. In a preferred arrangement of theinvention, the cam means 40 preferably comprises first and second campaths indicated generally at 64 and 65, respectively. In the full lineposition of the parts as shown in FIGURE 1, the apron 12 is retracted toits fully closed position with the lip portion 66 of the apron inengagement with the cutting edge 19 of bowl 11, which is the normallyclosed position of the scraper for transporting a load of materialcontained in the bowl. In order to open the scraper the power actuatingmeans 56 may be suitably energized by admitting fluid under pressure tothe port 57 of the cylinder 53 to effect movement of the piston rodmeans 54 to the right as viewed in the draw ing. Energization of poweractuating means in the manner noted effects sliding movement of theslide member 46 to the right providing for relative movement of theroller 42 with respect to cam 40 causing the apron 12 to pivot upwardlyabout pivot 33 toward the position indicated by the dotted lines of thebowl 11 in FIGURE 1. Preferably, the first cam path portion 64 isdesigned so as to provide for the maximum application of torque of thepower actuating means 50 over a predetermined range of initial openingmovement of the apron with respect to the bowl. After such initialopening movement, the roller 42 engages the second cam path portion 65which lessens the torque applied by the power actuating means 50 andincreases the angular velocity of movement of the apron 12 in thecontinued opening movement thereof. As before noted, maximum torque ishighly desirable in the initial stage of opening movement of the apronwith respect to the bowl in view of the load of the material in the bowlon the apron, and the positioning of the center of mass of the apronwith respect to the pivot axis 33. After such requirement for maximumtorque has been met and with lessening of the load on the apron anddisposal of the center of mass of the apron closer to the pivot axis 33,the torque applied by the power actuating means is lessened and theangular velocity of opening of the apron 12 to its fully open positionis increased.

In reverse energization of power actuating means 50, that isenergization of it in the opposite direction above described as byadmitting fluid under pressure through the port 58 of cylinder assembly53, the piston means 54 is moved to the left as viewed in the drawing sothat the initial return movement of the apron from its fully openposition to closed position is at relatively high angular velocity andlow torque by reason of engagement of roller 42 with second cam path 65,and upon engagement of the roller 42 with the first cam path 64 theangular velocity is decreased and the torque of the power actuatingmeans 50 is increased to power close the lip 66- of apron 12 with thecutting blade 19 of bowl 11. Thus, in the closing operation, should anydebris be collected or be caught between the lip 66 of the apron and thecutting blade 19 of the bowl the full torque of the power actuatingmeans 50 biases the apron toward its fully closed position with respectto the bowl, so the lip 66 and blade 19 will dislodge or break up anymaterial that may be disposed between the lip and the blade of the bowl.

While there has been shown and described a preferred embodiment of theinvention, it will be understood that various modifications andrearrangements may be made therein without departing from the spirit andscope of the invention.

The invention claimed is:

1. In an earth moving scraper having a bowl with an opening at one endthereof and an apron pivotally mounted on said bowl for opening andclosing said opening of said bowl, the combination of cam means and camfollower means between said apron and said bowl, power actuating meansfor effecting relative movement between said cam means and said camfollower means to provide for pivotal movement of said apron about itspivot for opening said opening of said bowl, and said cam means havng afirst cam path portion providing for substantially constant applicationof torque of said power actuating means over a predetermined range ofinitial opening movement of said apron with respect to said opening ofsaid bowl, and a second cam path portion providing for lessening thetorque applied by said power actuating means to said apron in thecontinued opening movement thereof by said power actuating means beyondsaid predetermined range of initial opening movement of said apron.

2. In an earth moving scraper having a bowl with an opening at one endthereof, a cutting edge at said opening, an apron pivotally mounted onsaid bowl for opening and closing said opening of said bowl, and a lipon said apron for registering with said cutting edge, the combination ofcam means and cam follower means between said apron and said bowl,double acting power actuating means operable in opposite directions foreffecting relative movement between said cam means and said cam followermeans to provide for pivotal movement of said apron about its pivot foropening and closing said opening of said bowl, said cam means having afirst cam path portion providing for substantially constant applicationof torque of said power actuating means in one direction of operationthereof over a predetermined range of initial opening movement of saidapron with respect to said opening of said bowl, a second cam pathportion providing for lessening application of torque and increasing theangular velocity of said apron in the continued opening movement thereofby said power actuating means beyond said predetermined range of initialopening movement of said apron, and said power actuating means in itsend position in the other direction of operation thereof biasing saidlip of said apron toward said cutting edge at said opening of said bowl.

3. In an earth moving scraper having a bowl with an opening at one endthereof and an apron pivotally mounted on said bowl for opening andclosing said opening of said bowl, the combination of cam means for saidapron, cam follower means engageable with said cam means, means formounting said cam follower means for movement on said bowl, poweractuating means supported on said bowl and connected with said camfollower means for effecting relative movement between said cam meansand said cam follower means to provide for pivotal movement of saidapron about its pivot for opening said opening of said bowl, and saidcam means having a first cam path portion providing for substantiallyconstant application of torque of said power actuating means over apredetermined range of initial opening movement of said apron withrespect to said opening of said bowl, and a second cam path portionproviding for lessening the torque applied by said power actuating meansand increasing the angular velocity of said apron in the continuedopening movement thereof by said power actuating means beyond saidpredetermined range of initial opening movement of said apron.

4. In an earth moving scraper having a bowl with an opening at one endthereof, a cutting edge at said opening, an apron pivotally mounted onsaid bowl for movement between opened and closed positions for openingand closing said opening of said bowl, and a lip on said apron forregistering with said cutting edge in the closed 6 position of saidapron, the combination of cam means for said apron, cam follower meansengageable with said cam means, means for mounting said cam followermeans for movement on said bowl, double acting power actuating meansoperable in opposite directions for effecting relative movement betweensaid cam means and said cam follower means to provide for pivotalmovement of said apron about its pivot for opening and closing saidopening of said bowl, said cam means having a first cam path portionproviding for substantially constant application of torque of said poweractuating means in one direction of operation thereof over apredetermined range of initial opening movement of said apron withrespect to said opening of said bowl, and a second cam path portionproviding for lessening application of torque and increasing the angularvelocity of said apron in the continued opening movement thereof by saidpower actuating means beyond said predetermined range of initial openingmovement of said apron, and said power actuating means in its endposition in the other direction of operation thereof biasing said lip ofsaid apron toward said cutting edge at said opening of said bowl.

5. In an earth moving scraper having a bowl with an opening at one endthereof, a cutting edge at said opening, an apron having arm meanspivotally mounted at one end on said bowl to provide for pivotalmovement of said apron between opened and closed positions for openingand closing the opening of said bowl, respectively, a lip on said apronfor registering with said cutting edge in the closed position of saidapron, the combination of cam means in said arm means of said apron,track means mounted on said bowl, slide means mounted for reciprocatingsliding movement in said track means, cam follower means engageable withsaid cam means and carried by said slide means, power actuating meanscomprising a cylinder and piston means reciprocable with respect to saidcylinder, said piston means being connected with said slide member, saidpower actuating means being energizable for effecting movement of saidpiston means and thereby effect relative movement between said cam meansand said cam follower means to provide for pivotal movement of saidapron about its pivot for opening said opening of said bowl, said cammeans having a first cam path portion providing for substantiallyconstant application of torque of said power actuating means over apredetermined range of initial opening movement of said apron withrespect to said opening of said bowl, and a second cam path portionproviding for lessening application of torque and increasing theangularly velocity of said apron in the continued opening movementthereof by said power actuating means beyond said predetermined range ofinitial opening of said apron.

6. In an earth moving scraper having a bowl with an opening at one endthereof, a cutting edge at said opening, an apron having arm meanspivotally mounted at one end on said bowl to provide for pivotalmovement of said apron between opened and closed positions for openingand closing the opening of said bowl, respectively. a lip on said apronfor registering with said cutting edge in the closed position of saidapron, the combination of cam means in said arm means of said apron,track means mounted on said bowl, slide means mounted for reciprocatingsliding movement in said track means, cam follower means engageable withsaid cam means and carried by said slide means, double acting poweractuating means comprising a cylinder mounted on said bowl and pistonmeans reciprocable with respect to said cylinder, said piston meansbeing connected with said slide means, said power actuating means beingenergizable for effecting movement of said piston means in oppositedirections for eifecting relative movement between said cam means andsaid cam follower means to provide for pivotal movement of said apronabout its pivot for opening and closing said opening of said bowl, saidcam means having a first cam path portion providing for substantiallyconstant application of torque of said power actuating means in onedirection of movement of said piston means over a predetermined range ofinitial opening movement of said apron with respect to said opening ofsaid bowl, and a second cam path'portion providing for lesseningapplication of torque and increasing the angularly velocity of saidapron in the continued opening movement thereof by said power actuatingmeans in said one direction beyond said predetermined range of initialopening of said UNITED STATES PATENTS 2,307,933 1/1943 Le Blell 37-126ABRAHAM G. STONE, Primary Examiner.

,apron, and said piston means in its end position in the 10 A. E.KOPECKI, AssistantExaminer.

1. IN AN EARTH MOVING SCRAPER HAVING A BOWL WITH AN OPENING AT ONE ENDTHEREOF AND AN APRON PIVOTALLY MOUNTED ON SAID BOWL FOR OPENING ANDCLOSING SAID OPENING OF SAID BOWL, THE COMBINATION OF CAM MEANS AND CAMFOLLOWER MEANS BETWEEN SAID APRON AND SAID BOWL, POWER ACTUATING MEANSFOR EFFECTING RELATIVE MOVEMENT BETWEEN SAID CAM MEANS AND SAID CAMFOLLOWER MEANS TO PROVIDE FOR PIVOTAL MOVEMENT OF SAID APRON ABOUT ITSPIVOT FOR OPENING SAID OPENING OF SAID BOWL, AND SAID CAM MEANS HAVING AFIRST CAM PATH PORTION PROVIDING FOR SUBSTANTIALLY CONSTANT APPLICATIONOF TORQUE OF SAID POWER ACTUATING MEANS OVER A PREDETERMINED RANGE OFINITIAL OPENING MOVEMENT OF SAID APRON WITH RESPECT TO SAID OPENING OFSAID BOWL, AND A SECOND CAM PATH PORTION PROVIDING FOR LESSENING THETORQUE APPLIED BY SAID POWER ACTUATING MEANS TO SAID APRON IN THECONTINUED OPENING MOVEMENT THEREOF BY SAID POWER ACTUATING MEANS BEYONDSAID PREDETERMINED RANGE OF INITIAL OPENING MOVEMENT OF SAID APRON.